Dashpot



Ma l8 1926.

H. L. MERRICK DASHPOT 1 amxmboz flerberfl. l rrzcl' 33x 711's Original ie gust 12. 1922 Patented May 18, 1926.

1 UNITED STATES HERBERT L. MEBBIGK, OF PASSAIC, NEVT JERSEY.

DASHPOT.

Original application filed. August 12 1922, Serial No. 262,316. Dividedand this application filed March This invention relates to dash pots foruse in connection with apparatus to prevent too sudden movementin somepart of the apparatus, the present application being a division of myco-pending application filed August 12, 1922, Serial No. 262,316, and itis the object of the invention to provide an improied device of thischaracter which is simple and'oheap in construction and highly eflicientand sensitive in use, the same being particularly adapted for use inconnection with automatic weighing mechanism, as set forth in myco-pending application hereinbefore referred to, to steady and preventchattering of the scale beam as the counter poise is moved alon the beamand approaches the point or perfect balance, although it is applicablefor use in connection with other kinds of apparatus.

In the drawing accompanying and forming a part of this specification,Figure 1 is a front elevation ofa portion of weighing mechanism showinga scale beam. with my invention applied thereto and the mountingthereof.

Figure 2 is a longitudinal sectional View of the dash pot.

Figure 3 is an end view of the plunger or piston forming-a part of thedash pot; and

Figure 4 is a cross sectional view of the cylinder of the dash pot,taken substantially on the line 4- 1 of Figure 2 looking in thedirection of the arrow. 7

Similar characters of reference designate like parts throughout thedifferent views of the drawing The embodiment of the inventionillustrated in the drawing comprises a liquid carrying casing orcylinder 5 closed at the bottom and arranged at said end with alaterally projecting flange 6 having perforations for the engagement ofsecuring means, such as bolts or the like, tor'mounting the cylinder ona fixed support. The upper end of the cylinder is open and has aremovable closure 7 with a perforation centrally thereof. A piston orplunger 8 is reciprocably carried in the cylinder by 'rod 9 extendingthrough the perforationin the-closure 7 and whereby the piston is connected to the movable part of theapparatus, such as the scalebeam 1'0eta weighing mechanism as in my co-pending application herein referredto and-to which reference may be had, to restrain such part from -hav-"ing-too sudden or v-i'olent movement and Serial No. 703,328.

steady the movenrent thereof, the piston being moved by and inaccordance with the movement of said moving part.

The dash pot is of a particular construction and arrangement to providea more eiiicient device of this character. To accomplish this result theinner wall of the cylinderis arranged with a restricted annular portionor annulus 11 located substantially midway between the ends withrecesses 12 arranged in the wall of the cylinder atopposite sides of theannulus, which recesses are in the nature of by-pass ports. The majorportion of the piston '8 is of less diameter than-the cylinder but hasan enlarged annular portion 13 substantially midway between theendsthereof, that is, it is of greater diameter at this portion, the wall ofthe piston converging or inclining toward the axis and from opposite!sides of said annular enlarged portion, as clearly shown in Figure 2,such enlarged portion being of a diameter to permit the same to have aslid.- ing fit with the cylinder annulus 11. The Wallet the piston atopposite sides of the annulus 13 is arranged with recesses 14 cutthrough the ends of the piston wall to cooperate with the cylinderrecesses 12 to bypass the liquid from the cylinder at one end of thepiston to the opposite end thereof. The piston has restricted ports 15in a web located in a plane with the annulus '13, which web is arrangedwith a hub 16 whereby the piston is mounted upon its actuating rod 9;The ports 15 permit a restricted flow of liquid from the cylinder at oneend of the piston to the opposite end-of the piston during the movementthereof. The inner wall of the cylinder 5 is also arranged withrestricted annular portions 18 and 19 at substantially equal distancesfrom and at opposite sides of the annulus 11.

In the use of the dash pot in connection with weighing mechanism.embodying a scale beam fulcrunred' or pivotally supported, as at 20, ina bearing 21 mounted upon the shelf 22 of the frame work of the weighingmechanism, and -having a load support, such as a platform, connectedthereto by a rod 23 passing through an opening in the-shelf 22, the loadbeing counterbalanced b-y a'counter poise 24" adjustable along the beam.

The dash-pot is-Imounted by inea-ns of the 'tlange- ..6 upon anauxiliary shelf 25 -suspended new the shelf 22 by' 'i'odjs iio; The

piston rod 9 passes up through an opening in the shelf and is pivotallyconnected to the scale beam, as at 27, adjacent the extremity of thelong;- end of the beam and alo- O which the want-earpoise adjustable.

in operation the connection of the piston with the moving part of anapparatut-i, such as the scale beam 10, is such so that ti 2 enlargedannular portion 13 of the pi ton is in register with the centralcylinder annulus 11 when the bean] is in position of equilibrium. As thepiston moves upward there will be a momentary -esistance to the movementthereof, the passage of the liquid from the cylinder at one end of thepiston to the opposite end being only through the restricted ports 15,but as the enlarged piston por tion 13 is moved out of register with thecylinder annulus 1]. the piston recesses M will come in register withthe cylinder recesses 12 permit-ting of an increased flow of the liquidpast the piston and as the piston moves upward due to the gradualrestiflting of the cylinder above the cylinder recesses 12 there will bea gradual decrease of flow of liquid past the piston, and as the pistonapproaches the restricted cylinder portion 18 the flow of the liquidpast the piston is restricted and thereby the movement of the pistonretarded, the flow of liquid being; only through the restricted pistonports 15. its the piston is brought to position of cquilibrium theenlarged piston portion Will be in register with the cylinder annulus 11increasing the resistance to the movement of the piston, the onlypassage of the liquid from one end of the piston to the opposite endbeing); through the restricted ports 15 and should there be any tendencyof the beam or other moving port to which the piston rod connected tovibrate upward or downward this will be checked by the resistance. ofthe liquid as the only passage of the liquid will be through therestricted pis ton ports.

Should the piston re moved suddenly downwardly the piston will coactwith the restricted cylinoer portion 19 in a manner similar to thatabove described in connection with the restricted cylinder portion 18,and as the piston moves to position of equilibrium any tendency to movethe piston upward from such position will be retarded by the oi'ilargodpiston portion coming into re n ister with the cylinder annulus ll.above described.

Having thus described the invention I claim:

1. A dash pot comprising a liquid carry- .ing cylinder having annularrestricted portions, and a piston to reciprocate in the cylinder, saidpiston being of less diameter than the cylinder to reciprocate in thecylinder and having an annular enlarged portion with relation to the.lelnainder of the ostess piston and said enlarged portion beingsubstantially of the same diameter as the restricted portions of thecylinder.

2. A dash pot comprising a liquid carrying cylinder having a restrictedannular portion centrally thereof, and a piston reciprocable in thecylinder of less diameter than the cylinder for the major portionthereof and having an annular enlargement of substantially the samediameter the restricted portion of the cylinder.

3. A. dash pot comprising a liquid carrying cylinder having a restrictedannulus intermediate the ends thereof with recesses in the cylinder wallat opposite sides of said annulus, apiston of less cross sectionaldimension for the major portion thereof than the cylinder reciprocablein the cylinder and havin a laterally enlarged portion intermediate theends, and recesses in the piston wall at opposite sides of said enlargedportion.

4-. A dash potcomprising a liquid carrying cylinder having an annularportion restricted in diameter in relation to the re n'iainder of thecylinder, apiston of less cross sectional dimension than the cylinder to'eciprocate in said cylinder having an annular enlarged portion relativeto the remainder of the piston and of substantially the same dimensionas the restricted portion of the cylinder, and bypass ports in the wallsof the cylinder and piston.

.il. dash pot comprising a liquid carrying cylinder ha ing an annularportion restricted in relation to the remainder of the cylinder withrecesses in the cylinder wall extending longitudinally thereof atopposite sides of said restricted portion, a cylindrical piston toreciprocate in said cylinder of less diameter for the maj or portionthereof than the cylinder, said piston int rmediate its ends beingenlarged to substantially the same diameter as the restricted portion ofthe cylinder and having a transverse web arranged with restrictedperforations for the purpose specified.

G. A. dash pot comprising a liquid carrying cylinder having an annularrestricted portion intermediate its ends, recesses extendinglongitudinally of the Wall of the cylinder at opposite sides of saidrestricted portion, a cylindrical piston havin a portionintcrinediateits ends of substantially the same diameter as therestricted portion of the cylinder with the walls of the piston atopposite sides of said enlarged portion converging outwardly, and thepiston having transverse web arranged with restricted perforations, anda rod to carry and reciprocate the piston in the cylinder.

7. In a dash pot, a liquid carrying cylinder havin an annular restrictedwall portion intermediate the ends thereof, with re cesses arranged inthe cylinder wall at opposite sides of said restricted Wall portion, anda piston having to reciprocate 1n the cylinder having a partsubstantially of the same diameter as the restricted cylinder portionwith recesses arranged at opposite sides of said piston part andrestricted ports therethrough for the purpose specified.

8. In a dash pot, a liquid carrying casing having a restricted portionintermediate the 10 ends thereof and restricted portions arranged atequidistant points at opposite sides of said intermediate restrictedportion, recesses in the casing wall at opposite sides of theintermediate restricted portion, and a piston having restricted portstherethrough to reciprocate in the piston.

Signed at Passaic, in the county of Passaic and State of New Jersey,this 7th day of March, 1924.

c HERBERT L. MERRICK.

